The present invention relates to see-through lenses. More particularly, the present invention is directed to uniquely constructed, radically-shaped lenses, e.g., spheric or toric lenses having a radius-of-curvature between 28–19 mm (19–28 base curve), adaptable primarily for use in non-prescription sunglasses, sport goggles and the like, although not limited thereto.
As well as enhancing vision, eyeglasses also serve to protect the eye against all types of foreign objects. Initially, the lenses employed in such eyeglasses were routinely made of glass and were substantially flat in shape, a condition that created significant distortion around the periphery of the lenses. More recently, lenses have been made of a variety of plastic or plastic-like materials, often having dramatically curved surfaces. For example, swim or riding goggles are well know to have teardrop-shaped lenses. While such lenses may reduce aerodynamic drag, a wearer may suffer from undesirable peripheral distortion when viewing through such lenses.
Curved lenses employed in sports goggles, sunglasses or the like may be more or less elliptical in shape as required by the specific application. Such applications may include fashion eye wear, performance eyewear including swim and sport goggles, and sunglasses, as well as all manner of protective eye wear for use at home and on the job. In any particular use, the arc of the curved lens may vary in shape dependent on the overall circumference of the curved lens necessary to achieve undistorted vision. Lenses may be employed with a slight spherical appearance, i.e., a modified spherical, or ovoid arc. In such slightly curved lenses, there is a variable radius of curvature somewhere between 106–44 mm, e.g., a 5–12 base curve (base curve being calculated by dividing a radius in millimeters into 530). In effect, the distance between the lens and eye may well differ at different locations on the lens. This may create significant distortion at the periphery of each lens.
The Government of the United States has procured a protective facemask assembly having a pair of semi-curved lenses of spherical or ovoid configuration. While these lenses may seem superficially similar to the present invention, closer inspection reveals a number of significant differences. Because the Government lenses are mounted in pockets creating the nose bridge of the facemask, the edge of each Government lens is truncated or cut-off to allow for assembly into its respective pocket. This naturally creates peripheral distortion for the wearer of the mask, when attempting to view through the truncated portion located near the mask nose. Another drawback of the Government procured spherical lens is the use of only a single size lens, i.e. “one size fits all.” Each Government lens also incorporates two parts, a spherical lens and surrounding flange joined by a dedicated and detectable seam. This seam itself can distort the vision of the wearer. Furthermore, there is no suggestion that the flange surrounding the Government's spherical lens can be made of any desirable configuration.
It is clear that there exists a need in the art for an improved viewing lens capable of providing distortion-free viewing in a fashionable design equally adaptable for use in most all types of eyewear including conventional, non-prescription sunglasses. As will become apparent, the present invention provides a uniquely configured lens assembly which optimizes peripheral vision while minimizing the size of each lens and thus maximizing the aerodynamic flow of air around the lens.